Electrostatic chucks are commonly used to hold substrates, such as semiconductor wafers, during various manufacturing processes. Such processes include, but are not limited to, ion implantation, physical vapor deposition, chemical vapor deposition, and etching. Electrostatic chucks typically include one or more electrodes embedded within a chuck body, sometimes referred to as a “puck,” which is typically formed at least partly of a dielectric or semi-conductive ceramic material across which an electrostatic clamping field can be generated. The electrostatic clamping field can securely hold a substrate to a face of the chuck body without the aid of mechanical retention mechanisms.
Electrostatic chucks offer several advantages relative to mechanical clamping devices and vacuum chucks. For example, electrostatic chucks mitigate the occurrence of stress-induced cracks in substrates which can occur when mechanical clamping devices are employed. Additionally, electrostatic chucks allow larger areas of substrates to be exposed for processing with little or no edge exclusion. Still further, electrostatic chucks are able to hold substrates against chucking surfaces with more uniform pressure distribution relative to other chucking means, thereby facilitating greater control over substrate temperatures when substrate heating and/or cooling devices are employed. Electrostatic chucks can also be effectively employed in low pressure or high vacuum environments.
Various processes that are performed on substrates, such as during the fabrication of integrated circuits, involve subjecting substrates to temperatures in excess of 200 degrees Celsius, and often up to about 450 degrees Celsius (C). However, conventional electrostatic chucks are generally only capable of operating up to a temperature of about 120 degrees C. When exposed to temperatures above about 120 degrees C., the components of many conventional electrostatic chucks will begin to fail. It would therefore be advantageous to provide an electrostatic chuck that is capable of operating at temperatures up to, an in excess of, about 450 degrees C. without experiencing heat-induced component failure.